Kazan Meslek Yüksekokulu / Kazan Vocational School

Permanent URI for this collectionhttps://hdl.handle.net/11727/2077

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Comparison of bacterial and fungal biodiversity of Turkish kefir grains with high-throughput metagenomic analysis
(2021) Ilikkan, Ozge Kahraman; Bagdat, Elif Seyma; 0000-0001-5843-6868; Q-9641-2019
Kefir is a health-promoting fermented drink having complex microbiota. This complex microbiota consists of bacteria and yeast association that is bound together with a polysaccharide called kefiran. To date, the complex microbiota of fermented foods was enlightened with culture-depended methods, however, recently, metagenomic studies have been started to use to reveal microbial diversity of fermented foods such as kefir. In this present study, we investigated the microbiome of two artisanal Turkish kefir grains (namely, A and G) by high throughput sequencing at the species level. Additionally, physicochemical analyses were carried out besides enumerations of lactobacilli, lactococci, total aerobic, and bifidobacteria in fermented milk kefirs. In these two kefir grains, different bacterial and fungal populations were revealed. In kefir grain A, Bifidobacterium longum was the dominant species while in kefir grain G, Lactobacillus kefiranofaciens was dominant. Concerning fungal diversity, in kefir grain A, Naumovozyma dairensis was the dominant yeast, while in kefir grain G, Zygosaccharomyces rouxii was dominant. High-throughput sequencing studies have revealed that kefir grains were typically dominated by lactobacilli. But, in this study, Bifidobacterium longum was found as a dominant bacterium in kefir for the first time.
The Effect Of Kefir Enrichment With Arthrospira Platensis And Chlorella Vulgaris On Kefir Microbiota, Antioxidant, And Physicochemical Properties
(2022) Kahraman Ilikkan, Ozge; Bagdat, Elif Seyma
This study evaluated the effect of Arthrospira platensis and Chlorella vulgaris on kefir microbiota, total phenolic content, antioxidant activity, and physicochemical properties such as pH, Brix, total dry matter, and titratable acidity. The results showed that the addition of algae at concentrations of 0.5% (w/v) and 1% (w/v) to the kefir did not change the acceptable physicochemical properties of kefir. The acidity of the microalgae-enriched kefirs increased with increasing algae concentration. Total phenolic content and antioxidant activity of all kefir samples fortified with algae were higher than those of the control. However, the addition of A. platensis exhibited better prebiotic activity than C. vulgaris on kefir microbiota during storage. Principal component analysis and overall results showed that A. platensis was a better candidate for improving the nutritional value of kefir.
Metataxonomic Sequencing To Assess Microbial Safety Of Turkish White Cheeses
(2022) Kahraman-Ilikkan, Ozge; Bagdat, Elif Seyma; https://orcid.org/0000-0001-5843-6868; 35277850; Q-9641-2019
High-throughput sequencing has provided a way to monitor the large diversity of microorganisms in fermented foods that have complex microbiota. Up to date, many kinds of cheese have been characterized with the metataxonomic approach, but the safety of unpacked Turkish white cheeses, which are widely consumed in Turkey, has not been assessed. In this study, fifteen unpacked white cheeses sold in public bazaars in Ankara province have been collected and subjected to microbial enumeration as well as physicochemical analysis. Five white cheeses, which have relatively the highest foodborne pathogens, out of fifteen white cheeses, have been analyzed by next-generation sequencing and metataxonomic analysis. According to the results, abundant families were Lactobacillaceae, Oceanospirillaceae, Enterococcaceae, Pseudomonadaceae, and Vibrionaceae. Staphylococcus aureus, E. coli, and Salmonella, which are indicators of bad hygiene and sanitation conditions, were found in cheeses. In conclusion, culture-independent methods such as metataxonomic can be important to evaluate the safety of foods.